Success with sandwiches - the bark beetle breeding story
20 October 2017
The key to controlling the pine bark beetle, which continues to devastate thousands of hectares of conifer forests in the Northern Hemisphere, may have been found in a laboratory in Auckland.
The New Zealand timber industry last night presented Plant & Food Research entomologist Graeme Clare with a special award for ‘science of international quality’ – a unique achievement in breeding pine bark beetles in the thousands needed for large scale research.
In New Zealand, bark beetles do not attack living radiata trees but China and India, the two main markets for our $2 billion worth of export logs, have strict fumigation requirements.
However the current treatment, methyl bromide, is being phased out worldwide. Industry body STIMBR (Stakeholders in Methyl Bromide Reduction) funded the beetle breeding project because it needed to test and verify lower levels of methyl bromide treatment and research potential replacements.
Graeme Clare knew that, despite the pressing need to breed the beetle in captivity for research, all previous attempts around the world had failed.
“So little was known about the insect, even how many stages it went through in its life cycle. We weren’t sure we could do it, but we had to try,” says Graeme.
The biggest hurdle, which had defeated all attempts so far, was to find and extract enough eggs from the insect’s tiny burrows in tree bark to meet the big production targets.
“We tried lots of different methods – dozens,” says Graeme. “If we couldn’t find a way to do this quickly and easily, we’d have failed too.”
The first major breakthrough came when Graeme tried pre-slicing the bark – actually the soft moist phloem inner layer of the bark – and packaging the phloem between plastic cards. It’s now a simple matter to disassemble the ‘bark sandwiches’ and extract eggs under a microscope.
The team then went on to design and test every aspect of insect management - diet, microbe and fungus control, storage, airflow, temperature, humidity and transport for two different species before they could finally produce enough insects of a consistent quality for the demanding production schedule.
The world’s only bark beetle raising facility has now produced around 200,000 insects and collects more than 20,000 eggs a month.
Senior Communications Advisor, Corporate Communications,
Plant & Food Research Mt Albert,
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